1. Field of the Invention
The present invention relates to a thin film transistor array (TFT array) and repairing method thereof. More particularly, the present invention relates to a thin film transistor array (TFT array) and repairing method thereof, which can significantly improve yields of a repair process.
2. Description of Related Art
The proliferation of multi-media systems in our society depends on development of semiconductor devices and display devices. Display devices such as the cathode ray tube (CRT) have been used for quite some time due to its remarkable display quality, reliability and low costs. Although the conventional CRT has many advantages, the design of the electron gun renders it heavy, bulky and energy wasting. Moreover, there is always some potential danger of hurting viewer's eyes due to its emission of some radiation. With big leaps in the techniques of manufacturing semiconductor devices and opto-electronics devices, high picture quality, slim, low power consumption and radiation-free displays such as the thin film transistor liquid crystal displays (TFT-LCD) have gradually become mainstream display products.
Generally, a color TFT-LCD includes a color filter (C/F), a TFT array and a liquid crystal layer disposed therebetween. The TFT array includes a plurality of thin film transistors, which are arranged in an area array and are connected with a plurality of scan lines and data lines. Each thin film transistor is disposed in a pixel area and is electrically connected to a corresponding pixel electrode formed by indium tin oxide (ITO), indium zinc oxide (IZO) or other transparent conductive materials. Each thin film transistor is used to drive the liquid crystal layer to show various gray levels. Furthermore, in a pixel of the conventional TFT array, a storage capacitor (Cst) may be formed between a pixel electrode, the corresponding scan line and a dielectric layer. (e.g. a gate insulating layer and/or a passivation layer) Also, the storage capacitor (Cst) can be formed between a pixel electrode, a common line and a dielectric layer to provide better picture quality.
However, during a patterning process of the pixel electrodes of the conventional TFT array, two adjacent pixel electrodes may abnormally connect to each other because of an ITO or IZO residue therebetween. Furthermore, particles or defects within the dielectric layer of the storage capacitor resulting from contamination may cause the leakage between an upper electrode and a bottom electrode of the storage capacitor. The particles or defects make pixels display abnormally and the picture quality of the display is degraded. In order to resolve the problems mentioned above, a laser welding process between the upper electrode and the bottom electrode of a defective storage capacitor is performed to darken a defective pixel. It is noted that the number of the dark defects is increased because the laser welding process mentioned above is performed.